With the fast development of display technology, touch screen panels have become popular in people's life gradually. At present, according to constitution structures, touch screens may be classified into add-on mode touch panels, on-cell touch panels and in-cell touch panels. For an add-on mode touch panel, the touch panel and the liquid crystal display (LCD) are produced separately and then attached together to form a liquid crystal display with touch function. Add-on mode touch panels suffer disadvantages such as high manufacturing cost, low light transmission rate and thick assembly. For an in-cell touch panel, touch electrodes of the touch panel are embedded inside the liquid crystal display, which can reduce the overall thickness of the module, and can drastically reduce manufacturing costs of the touch panel. Therefore, in-cell touch panels have received great attentions from panel manufacturers.
At present, an in-cell touch panel detects the touch position of a finger in accordance with the mutual capacitance or self-capacitance principle. For the self-capacitance principle, it is possible to provide a plurality of self-capacitance electrodes disposed in the same layer and insulated from each other in the touch panel. When a human body does not touch the screen, each self-capacitance electrode experiences capacitance at a fixed value. When a human body touches the screen, respective self-capacitance electrodes experience capacitance that is at a value of the fixed value plus the body capacitance. The touch sensing chip can determine the touch position by detecting capacitance value variation of self-capacitance electrodes in the touch peirod. Since the body capacitance can act on all the self-capacitances, as compared to the approach in which the body capacity that can only act on projection capacitance in accordance with mutual capacitance principle, the touch variation caused by the touch of a body on the screen would be greater than that of the touch panel manufactured in accordance with the mutual capacitance principle.